In many situations, as for example in housekeeping activities for hotels, containers such as spray bottles need to be filled at frequent intervals with a cleaning solution or other mixture of water and liquid chemicals. Typically, such mixtures are obtained by passing a stream of water through a venturi which draws a liquid chemical from a concentrate source into the water stream that is discharged into the container.
If air is allowed to be entrained with the water/chemical stream discharged into the container, many cleaning solutions and other mixtures tend to foam quite strongly. As a result, foam overflows the container even if the container is nowhere near filled with liquid. Consequently, much time is wasted because either the container must be filled unnecessarily often, or the operator must fill the container very slowly.
Another related problem arises from the fact that the venturi devices require an air gap, i.e. a device which breaks any accidental siphon, so as to prevent water in the venturi from flowing back into the public water supply. In practice, the filling apparatus is typically mounted on a wall. Most conventional air gap devices of the type useful in such filling apparatus have a tendency, albeit small, to spit and splash spray water outwardly of the air gap device. This spray, and the resulting drip, is annoying and, over a period of time, tends to damage the wall and make the apparatus unsanitary.
Prior to the present invention, water public safety authorities would only approve for this purpose a completely open air gap device which would cause the above-described foaming, spitting and splashing. With the use of the present invention, applicants have been successful in obtaining local and national water authority approvals for anti-foaming splashproof venturis throughout the United States and many parts of the world.